In many instances, one of the most critical systems for aircraft can be the pitot-static system operative to determine the airspeed and/or altitude of the aircraft inflight. Aircraft having dual controls can include separate, yet integrated, pilot and co-pilot systems. Many aircraft may employ a pitot tube having a combination of at least one forward-facing aperture and a plurality of orthogonal apertures, disposed about the circumference of the tube. In-flight, the total or impact pressure (Pi) of the airstream can be captured by the forward-facing aperture (i.e., the pitot port) as the airstream rams and stagnates, i.e., decelerates to essentially zero (0) kts. When disposed in a region of relatively undisturbed flow, the orthogonal apertures can measure static pressure (Ps) which is a direct measurement of the free stream airflow from which altitude and rate of climb may be derived. By using the values of static pressure (Ps) and impact or total pressure (Pi), the aircraft instrumentation system can derive measurements for airspeed and Mach number.
A related system, which may be equally flight critical, is the Automatic Dependent Surveillance-Broadcast (ADS-B) system. This system may use a radio transmitter or radar transponder to broadcast aircraft position and flight plan information to other aircraft flying in the same regional airspace. More specifically, the ADS-B can transmit information concerning altitude (ASL), airspeed (A/S), and location data to area ground stations, and to other ADS-B-equipped aircraft in the vicinity. While air traffic controllers use the information for traffic management, i.e., keeping aircraft some threshold vertical and/or lateral distance from each other, the ADS-B is particularly valuable over large bodies of water, e.g., the Atlantic or Pacific oceans, where aircraft are often out of the range of control towers/air traffic control. Accordingly, the pilots of each aircraft are individually responsible for maintaining a safe distance between their aircraft and others passing in close proximity. As such, a pilot is trained to listen for broadcast information and make flight plan adjustments, e.g., increase or decrease altitude, change heading, etc., to maintain a safe separation distance between the operated aircraft and an approaching aircraft.
Presently, many aircraft operators perform routine maintenance/testing of both the pitot-static and transponder systems after a threshold number of flight hours, or after an alert has been issued by the on-board aircraft diagnostic system. Generally, each system requires dedicated hardware, firmware and/or software to run a series of tests corresponding to predefined in-flight conditions. That is, the pitot-static air data system employs an Air Data Test Set which connects to the pitot and static ports of an aircraft via a number of hoses and fittings, while the ADS-B system is tested for operation of the transponder and the issuance/broadcast of the correct longitude, latitude, airspeed and altitude data relative to sea level (i.e., while the aircraft is on the ground).
In addition to the cost of owning and operating separate test systems, i.e., an Air Data Test System (ADTS) and an Automatic Dependent Surveillance-Broadcast (ADS-B) test set, each system offers its own unique challenges of operation, i.e., errors during test. With respect to the ADTS, even small pneumatic air leaks in the system can produce significant/sizeable variations in altimeter readings. For example, an error/variation as small as 0.1 millibars in air pressure will result in a variation of eighty (80 feet) of vertical height.